Merge pull request #2686 from rn/random

qemu: Use /dev/urandom on Linux for virtio-rng-pci

src/cmd/linuxkit/run_qemu.go

@@ -521,6 +521,12 @@ func buildQemuCmdline(config QemuConfig) (QemuConfig, []string) {
 		}
 	}
 
+	rng := "rng-random,id=rng0"
+	if runtime.GOOS == "linux" {
+		rng = rng + ",filename=/dev/urandom"
+	}
+	qemuArgs = append(qemuArgs, "-object", rng, "-device", "virtio-rng-pci,rng=rng0")
+
 	var lastDisk int
 	for i, d := range config.Disks {
 		index := i